Few 'essential' federal employees?

I note in this article that the EPA and HUD indicated that 6 percent of their employees were "essential." While many of the remaining 94 percent are surely very important to all of us, I cannot help wondering whether payrolls are being padded to give governmental departments unwarranted significance, and if taxpayers' money isn't being used to employ many individuals in these, and in other departments, who aren't really needed. The shutdown should never have occurred, but the information it uncovers must not be ignored.